1. Field of the Invention
The present invention relates to a screen printing apparatus, and more particularly to a screen printing apparatus that screen-prints a cream solder, an electrically conductive paste, or the like on a substrate, such as a printed wiring board (PWB), as preprocessing for mounting electronic components on the substrate.
2. Description of the Related Art
A screen printing apparatus is installed in a printed circuit board (PCB) manufacturing line, as described in Japanese laid-open Publications, for example, H7-205399. The screen printing apparatus performs screen printing of an electrically conductive paste or the like on substrates conveyed from the upstream side, and delivers the substrates after printing to a component mounting apparatus located on the downstream side. In most screen printing apparatus of this type, a single printing unit installed in the apparatus receives the substrates one by one, and delivers, upon performing the printing processing thereon, to the component mounting apparatus. Therefore, the path of the substrates conveyed to and from the screen printing apparatus is set in the center of the screen printing apparatus, and the printing position at which the screen printing is performed is fixedly set at a center position on the substrate conveying path.
However, a demand has recently grown for a configuration in which a substrate support table that supports the substrates can move in a specific direction orthogonal to the substrate conveying direction and which is imparted with a switching function for switching the conveying path of the substrate on the substrate support table in the specific direction orthogonal to the conveying direction. However, if the printing position is fixedly set to the center position on the substrate conveying path, then such configuration can cause a problem that the substrates is required to pass undesirable routes, thereby decreasing the throughput.